Panel with Relay and SPD, Installation?

[jowjow]

Hello and thanks for the interest. I have a little dilemma and was unable to get an answer anywhere.

I'm trying to fit a SPD and an over/under voltage protector to my existing "Main Switch" and "RCD" setup. my question: is the location of the SPD and surge protector correct? thanks

 

[Sparkingmad]

Hello and thanks for the interest. I have a little dilemma and was unable to get an answer anywhere.

I'm trying to fit a SPD and an over/under voltage protector to my existing "Main Switch" and "RCD" setup. my question: is the location of the SPD and surge protector correct? thanks

What is the current rating rating of your surge protector? I have fitted Dehn SPD’s at a factory this year and to simplify matters the units are rated for 125A with big terminals so you can fit them without going through a Mcb first and Just off the main switch. If you use smaller cable to connect them then they come off a suitable rated mcb.

 

[jowjow]

thanks for the message. mine is rated some 40 - 60a. wiring goes to the spd after the main switch as per diagram, thanks

 

[snowhead]

Whats' the reason for the Under / Over Voltage unit?

 

[Sparkingmad]

thanks for the message. mine is rated some 40 - 60a. wiring goes to the spd after the main switch as per diagram, thanks

What’s the rating of the incoming service, ocpd?

 

[jowjow]

Whats' the reason for the Under / Over Voltage unit?

its so that if voltage is too high or too low it is cut hence does not damage appliances. its also required by law in my country.

 

[jowjow]

What’s the rating of the incoming service, ocpd?

40a - note that in my country we use 240v

 

[pc1966]

It looks like your main switch is in fact a double-pole MCB, is that correct?

Nothing wrong with doing that provided it is appropriate for the load, etc, but it would make selectivity with any down-stream MCB/RCBO very difficult to achieve (unless its instant trip point is above the PFC/PSSC of your supply at that point).

As already said above, many of the SPD are designed to be safe with supply fuses of up to 125A (or more) so you can normally get away with the supply's own fuse and use a simple DP switch. However, if your choice of SPD specifies a smaller breaker then you need to look at the design more carefully.

 

[jowjow]

It looks like your main switch is in fact a double-pole MCB, is that correct?

Nothing wrong with doing that provided it is appropriate for the load, etc, but it would make selectivity with any down-stream MCB/RCBO very difficult to achieve (unless its instant trip point is above the PFC/PSSC of your supply at that point).

As already said above, many of the SPD are designed to be safe with supply fuses of up to 125A (or more) so you can normally get away with the supply's own fuse and use a simple DP switch. However, if your choice of SPD specifies a smaller breaker then you need to look at the design more carefully.

thanks for the detailed explanation. yes the diagram is of a double pole mcb but as per the text its just a main switch (a manual on/off). the switch is rated as 40a and the spd is rated at up to 60a. the spd is the one below:

 

[pc1966]

That is 60kA peak surge current, almost certainly for a 8/20us waveform.

You need to look up the data sheet to see what the maximum over-current protection is, and check that is above the incoming supply fuse.